I always put chairs behind my house stewards and servants, so they can have a seat when they're tired of standing, because "reasons of immersion". And I do know about air-snapping. I try not to use it.

Lalafells on step stools are immersive. But a step stool on a box on a chair on a bed on a table with a lalafell on top of all that, just because you wanted to build a tower to reach second floor from the first, is less so. My long string of text was to express that what I think, is the official stance which is "they do not approve of furniture-towers either". Not to mention a stacking feature may introduce coding difficulties and stability checks, to record positioning of furnitures upon furnitures.